Dispensing apparatus for a volatile liquid

ABSTRACT

A dispenser for a volatile liquid is intended to be used in a vehicle. It comprises a substantially closed conical container ( 2 ) for the liquid, and a pair of plates ( 14, 28 ) closing the top of the container form between them a capillary interface ( 88 ) leading to a disseminating porous element ( 42 ). While the vehicle is in movement, liquid is thrown upwards and outwards by accelerations of the vehicle to the plates and so to drawn through the capillary passages at the interface to reach the porous element. The container is pivoted at its lower region to be tiltable through a similar angle to tilt of the liquid surface, so that all the liquid can reach the plates and so be dispensed.

The invention relates to apparatus for dispensing volatile liquids, suchas fragrances and air freshening substances. It is particularlyconcerned with such dispensing apparatus for use in vehicles, especiallyroad vehicles.

One problem encountered with the use of liquid fragrances and freshenersin road vehicles is that there are frequent periods, often lengthy, whenthe vehicle is not in use but the liquid continues to volatilise. If thevehicle interior is completely closed, as is often the case when thevehicle is not in use, high concentrations of the volatilised materialcan accumulate in the atmosphere in the vehicle, especially as theclosure of the interior frequently results in a considerable temperatureincrease. The result can be unpleasant for the occupants when thevehicle is next used, and is wasteful of the material being dispensed.

It is an object of the invention to at least ameliorate these problems.

According to one aspect of the invention, there is provided a dispensingapparatus for a volatile liquid comprising a container having asubstantially closed interior space for the liquid and at least onecapillary passage for communication with the exterior extending from anupper region of the interior space adjacent an upwardly extending wallor partition of the container, whereby liquid displaced onto said wallor partition to reach said at least one capillary passage can be drawntherethrough to be released from the container.

With such an apparatus located in a moving vehicle, the inertia of theliquid causes it to be displaced in the container as the vehicle changesspeed or direction. By arranging that the liquid then reaches said atleast one capillary passage it can be dispensed from the container whilethe vehicle is moving.

Preferably, the container is mounted on a support in an upright positionbut is tiltable thereon by a transverse inertia force in the samedirection as the direction of displacement of the liquid. The containercan thus be itself displaceable by inertia forces generated during themotion of the vehicle, so that its tilting will assist the displacementof the liquid towards said at least one capillary passage.

According to another aspect of the invention, a dispensing apparatus isprovided for a volatile liquid, comprising a container withsubstantially closed interior space having at least one capillarypassage opening into an upper peripheral region of the interior spacefor communication with the exterior, and a mounting on which thecontainer is tiltably supported, return means acting between themounting and the container urging the container to an upright positionon the mounting, the container being able to tilt against the action ofsaid return means under the influence of inertia forces actingtransversely upon it.

Preferably, the container is in the form of a bowl with a side wallsloping upwards and outwards from a central bottom region towards saidat least one capillary passage. The angle of slope to the horizontalwill normally be at least 15°, but can be considerably greater. Inparticular, if the container is arranged to be tiltable, an angle ofslope of between 30° and 60° is preferred. At least the upper region ofthe side wall can conveniently have a substantially conical shape.

In a dispenser according to the invention, it is convenient to arrangesaid at least one capillary passage to open into the interior of thecontainer adjacent around substantially the entire periphery of thecontainer upper region so that said passage or passages can collectliquid displaced in any direction from the lower region in which it isnormally at rest.

In a particularly convenient arrangement, the container is rotationallysymmetrical and a pair of abutting or closely adjacent plates extendingclose to the periphery of the container upper region form said capillarypassage or passages at their interface, so that liquid reaching theinterface at any point around the periphery is drawn through the passageor passages inwards by the capillary action to a central upper region ofthe container from where it can escape to the exterior. Preferably, atthe outlet end of the passage or passages there are distribution meansto assist the volatilisation and dispersion of the liquid.

Any ability of the container to tilt in response to disturbing forcesgenerated by the movement of the vehicle is preferably limited, to limitthe exposure of the liquid to said capillary passage or passages. Thismaximum angle of tilt may be related to any initial slope of the wall orpartition along which the liquid travels;

desirably, the tilt is limited to give the container wall a final slopeat a minimum angle of not substantially less than 15° to the horizontal,and preferably not substantially less than 25°. The liquid will ofcourse also be tilted and it may be arranged that under normalmanoeuvring conditions the liquid surface tilt will approximatelycorrespond to the final angle of slope of the container wall adjacentthe capillary passage.

The depth of liquid at rest in the container is another factor, and in afurther preferred feature, means are provided to limit the filling levelof the container to some distance below said at least one capillarypassage, so that the displaced liquid does not reach the passage tooeasily due to overfilling.

By way of example, an embodiment of the invention will be described inmore detail with reference to the accompanying drawings, in which:

FIG. 1 is an axial sectional view of an apparatus according to theinvention at rest,

FIG. 2 is a similar view showing the apparatus tilted when in use, and

FIG. 3 is a sectional illustration of a refill capsule for the apparatusof FIGS. 1 and 2.

The apparatus comprises a rotationally symmetrical container 2 having abowl-form interior 4 widening upwards from a relatively narrow lowerregion. In the illustrated example the container thus has a generallyconical form, the side wall 6 being inclined at an angle of about 50° tothe horizontal. Continuing from the inclined side wall 6, the containerterminates at the top with a short cylindrical wall 8.

Fitting within the wall 8 is a top closure 10 comprising an upper wall12 sealed at its outer edge to the wall and a lower wall 14 spaced fromthe upper wall by an integral, downwardly turned inner wall 16. The topclosure walls, with the wall 8, enclose an annular space 18 sealed fromthe exterior but open to the remainder of the interior through a narrowgap between the container wall and the closure lower wall 14.

An inner member 22 comprising a central boss 24 projecting through acentral opening 26 in the annular lower wall 14 has an integraldisc-form skirt 28 which, like the closure lower wall 14, extends closeto the container inner wall. The skirt 28 is urged into contact with thelower wall 14 by a spring 34 compressed between the bottom of thecontainer and a metal bearing plate 36 that abuts the skirt 28. In theboss 24 is a filling aperture 38 through which the liquid to bedispensed can be put into the container.

The container 2, the top closure 10 and the inner member 22 may bemoulded from a plastic material such as Deirin (TM). The metal bearingplate 36 spreads the spring load acting on the skirt 28 to ensure thatthere is close contact between a substantial area of the closure lowerwall 14 and the inner member skirt 28, so that their abutting faces actas capillary faces, ie. capillary passages being formed between them, aswill be described below.

The closure lower wall 14 extends inwardly past the inner wall 16 butthe relatively large central opening 26 is overlapped by the innerregion of the skirt 28. The inner edge 26 a of the lower wall around theaperture 26 is chamfered to form an acute-angled recess with theadjoining face of the skirt 28.

A porous sheet element 42 is secured in the central aperture 26 of theclosure lower wall by a spring ring 44 fitting into the recess. Thesheet element 42 is initially a flat disc with a central hole throughwhich the boss 24 projects. When the spring ring 44 is put in place, itforces the element 42 into the acute-angled recess and the abutting edge26 a of the aperture forces the outer margins of the element 42 upwardsinto a generally curved pleated shape.

In the present example, the sheet element 42 is made of Unisorb basepaper U1 45 gm/m² manufactured by Devon Valley Industries Limited ofExeter, Devon, but any sheet material having the required degree ofporosity and stability of shape can be used, preferably having a lowbulk as a thin sheet will hold less liquid at any instant.

A protective cover 52, secured to the annular shoulder formed betweenthe lower and inner walls 14,16 lies over the sheet element 42. A largecentral aperture 54 in the cover is located over the boss 24. A seriesof further apertures 56 are provided in the cover 54, overlying theouter margins of the sheet element 42.

The container is mounted on a base support 62 to which it is attached bya flexible connecting element 64, e.g. a nylon cord. The cord 62 has aball end 66 that is passed through the central bore 62 a on assembly andis held in the free end of a leaf spring 68 projecting into the hollowsupport 62 from the bottom rim 70 of the support. The spring 68 appliesa tension to the element 64 to hold the container normally upright, withits bottom face 72 against a bearer plate 74 set into a recess 76 in thetop face of the support 62. The container bottom face 72 and thecontacting top face 74 b of the bearer plate 74 are surfaces ofrevolution concentric to each other. The tension element 64 passesthrough their central axis and is maintained in that central position bya clearance hole 74 a in the plate in which it can slide freely. Flexureof the spring by the tension in the connecting element forces the springagainst a screw 78 threaded into a bore 80 to extend generally parallelto the spring, close to its upper face. Adjustment of the screw inwardsand outwards (see FIGS. 1 and 2), respectively increases and reduces thetension in the connecting element.

The abutting top and bottom faces 72, 74 b are so formed that, in aposition of rest in which the container and support are concentric witheach other, as shown in FIG. 1, they make contact over a disc-form areain a central region extending some distance radially from the centraltension element. Outwardly from that area there is an intermediateannular region in which the faces diverge from each other at aprogressively increasing rate. Beyond that annular region, there is anouter region in which the distance between the faces lessens. In theillustrated configuration, these characteristics are obtained by using aplate 74 having a flat top face 74 b surrounded by upstanding rim 82 ofthe recess 76, and forming the container bottom as a hemisphere with thecontact face 72 as a central flat around the tension element 64.

As already described, the apparatus is intended to be mounted in avehicle to act as a dispenser for a volatile liquid such as a fragrance.The base support 62 is fixed in place with the central axis of theapparatus preferably vertical, but in any event in a more or lessupright rest position, as will be clear from the following descriptionof its operation.

In use, the liquid fragrance fills the lower region of the container toa level L when the apparatus is in the rest position shown in FIG. 1. Inthis position the liquid, when it vaporises, can escape only through thesmall filling aperture 38 in the inner member 22 from which it willdissipate at so slow a rate as not to be hardly noticeable, if at all.However, when the vehicle is driven, from changes of speed and ofdirection of travel its motion will create inertia forces in the liquidand the container in all directions transverse to the central axis ofthe container. The liquid will flow to one side or the other of thecontainer in direct dependence to the inertia force it experiences,towards a peripheral region of the capillary faces of the plates 14,28.Because of the rotational symmetry of the container and the plates 14,28this effect is independent of the direction of tilt.

The central flat contact face 72 bearing on the support 62 willinitially resist any lateral inertia forces acting on the container 2,which tend to displace the container in the same direction since itscentre of gravity is above the support. However, once those forcesexceed a minimum value required to allow it to overcome the restoringtension in the flexible element, the container will tilt on the supportto an increasing degree in dependence upon the force experienced, untilit contacts the rim of the support. This occurs at an angle of tilt ofthe container axis of about 25° and preferably not more than 30° to thevertical. The tilting of the container complements the displacement ofthe liquid under its own inertia, so bringing the liquid more readilyinto contact with the two capillary plates at a peripheral region. Inthe example of the illustrated embodiment, the apparatus is arranged foran expected angle of tilt of the liquid surface of some 25° to 30° tothe horizontal. The tilt of the liquid and of the wall of the containeron which it rests are thus substantially equal as illustrated in FIG. 2.

While the two plates 14,28 are forced into contact with each other, theywill not have perfect planar matching faces, so that there are passagesin the interface 88 between the plates into which liquid can be drawn bycapillary action. Liquid reaching the outer edges of the plates istherefore drawn across the interface of the plates 14,28 to the inneredge 26 a where it is adsorbed by the porous sheet element 42 in theacute-angled recess. The liquid thus spreads over the surface of thesheet element 42 to be exposed to the external atmosphere, in particularover the upstanding generally cylindrical margin of the element, fromwhere the fragrance vaporises readily. The disseminating sheet element42 will continue to draw liquid from the recess as long as it issupplied by the capillary action in the interface 88 between the plates14,28. As soon as the disturbing force ceases, however, allowing thecontainer and its contents to return towards the rest position, thesupply of liquid ceases.

Because of the close contact between the plates 14,28, the capillarypassages contain only a very small volume of liquid so the fragrancequickly reaches the element 42. Accordingly, there is a relatively rapidresponse in the initial release of the fragrance due to liquid beingtaken up by the plates. Similarly, because only a small amount ofmaterial can be taken up by the plates 14,28 and porous sheet element42, very little need be released when the journey is ended and thedispenser is no longer subject to tilting disturbances, so that thefragrance is used economically.

When the vehicle is at rest, it is of course possible that it is on anincline so that the apparatus is tilted even though the container hasbeen centralised on the base support. However, in the illustratedexample the side wall of the container is sufficiently steep to preventthe liquid reaching the capillary passages under any probable staticconditions.

While the apparatus is not mounted in place it is possible that it couldbe mishandled and turned upside down. Should that happen, the liquid inthe container will run into the annular space 18, so reducing any riskthat the capillary passages between the plates 14,28 will be flooded andexcess liquid will spill from the container. The liquid is in any caseprevented from spilling from the filling opening 38 because the openingcommunicates with the interior through an extension tube 90 projectingdownwards some distance below the lower skirt 28. The presence of thetube 90 also makes it difficult to overfill the container. Limiting theupper level of the liquid in the container at any time also limits therisk of dispensing liquid unnecessarily when the vehicle is parked on anincline.

The container 2 can take other shapes than that shown. The small baseand sloping sides of the generally conical form shown has the advantagethat most if not all of the liquid in the container is able eventuallyto run to the outer margins of the capillary plates under the action ofthe lateral disturbing forces experienced during motion of the vehicle,so there need be little or no wastage.

Similarly the angle of tilt required for the container will depend tosome extent on the shape of the container. If a very shallow containeris employed, for example if the side wall is inclined at a relativelysmall angle to the horizontal it is possible to rely solely on thelateral displacement of the liquid under its own inertia. Under normaldriving conditions, it can be assumed that the inertia forces on theliquid can tilt its surface some 20-30° to the horizontal. If thecontainer were rigidly fixed in place, therefore, the side wall wouldrequire a similar slope to allow most if not all the liquid to bedispensed. A significantly smaller angle of slope should be avoidedhowever, to limit unwanted dispersal of liquid when the vehicle isparked on an incline.

By making the container tiltable in use, all risk of the liquid reachingthe capillary plates, when the vehicle is parked, can be avoided, if theslope of the side wall is sufficient. To achieve this effect, it isdesirable, in general, that the container has a side wall that slopes inits upper region extending between the surface of the liquid at rest andthe capillary plates, at an angle of not less than 25° and preferably atleast 30°, while the container should be capable of tilting through anangle of at least 10°, and preferably at least 20°, from its restposition. It will be understood, moreover, that the ability of thecontainer to tilt can also allow the occupant of the vehicle to operatethe dispenser manually, if so desired, when the vehicle is parked.

Of course, the steepness of the container side wall keeps the liquidfrom the capillary plates only while the vehicle is at rest and thetilting capability under acceleration, whether sideways or fore and aft,can be arranged to counteract the initial incline of the side wallcompletely. By arranging that expected incline of the liquid surface tothe horizontal is at least equal the tilted incline of the side wall, asshown in FIG. 2, no residue of liquid is left that cannot reach theplates 14,28.

To facilitate refilling it is preferred to provide single-chargeflexible wall capsules 92 of the form shown in FIG. 3. When the capsulesealing cap 94 is removed, a skirt 96 surrounding an outlet tube 98 canbe located over the boss 24, so that the tube 98 extends into thefilling opening 38 and the capsule is then squeezed to discharge itscontents. Such a capsule carrying a charge of, e.g. 3.5 ml of liquid,will fill the container to the level L shown in FIG. 1, somewhat belowthe level of the extension tube.

Many modifications of the apparatus described are possible within thescope of the invention. For example, although the illustrated embodimentrelies on movement of the liquid across a side boundary wall of thecontainer in which it is held, it is also possible to arrange aninternal partition to provide a path for the displacement of the liquid.Also, although the illustrated embodiment utilises the interface betweena pair of plate members for capillary action on the volatile materialother forms of capillary passage can be provided, including amultiplicity of discrete passages.

What is claimed is:
 1. Dispensing apparatus for a volatile liquidcomprising a container having a substantially closed interior space forthe liquid and at least one capillary passage for communication with anexterior extending from an upper region of the interior space adjacentan upper portion only of an upwardly extending wall or partition,whereby only liquid displaced onto the upper portion of said wall orpartition can reach said at least one capillary passage to be drawntherethrough to be released from the container, wherein the container ismounted on a support in an upright position but is tiltable thereon by atransverse inertia force in a same direction as a direction ofdisplacement of the liquid.
 2. Apparatus according to claim 1, whereinthe container is supported on a mounting so as to be tiltable about anaxis below a center of gravity of the container and return means urgingthe container to an upright position on the mounting against any tiltingforce experienced by the container.
 3. Apparatus according to claim 2,further comprising means for limiting tilting displacement of thecontainer on the support.
 4. Apparatus according to claim 3, whereinsaid tilting displacement is limited to give the container wall orpartition a minimum angle of not substantially less than 15° to ahorizontal.
 5. Apparatus according to claim 2, wherein the container isheld on the support by resilient means urging the container downwardsonto the support.
 6. Apparatus according to claim 5, wherein thecontainer is rotationally symmetrical and is held by said resilientmeans to be tiltable in any direction transverse to an axis of symmetryof the container.
 7. Apparatus according to claim 6, wherein theresilient means maintain a bearing contact between the container and thesupport that moves laterally away from a tension element with increasingtilt.
 8. Apparatus according to claim 6, wherein said at least onecapillary passage occupies a substantially annular area and extendsaround a periphery of the interior space at the upper region. 9.Apparatus according to claim 8, wherein communication with the exterioris at a center of an annulus of said at least one passage, with anemanator at said center for said liquid.
 10. Apparatus according toclaim 8, wherein the container comprises a bowl with a peripheral sidewall sloping upwards from a central region forming lateral boundaries ofthe interior space.
 11. Apparatus according to claim 1, wherein said atleast one capillary passage is formed at an interface of a pair ofabutting planar surfaces.
 12. Apparatus according to according to claim1, wherein the container comprises a bowl with a peripheral side wallsloping upwards from a central region forming lateral boundaries of theinterior space.
 13. Apparatus according to claim 12, wherein said atleast one capillary passage occupies a substantially annular area andextends around the periphery of the interior space at the upper region.14. Apparatus according to claim 12, wherein the bowl has a half-coneangle not substantially less than 25°.
 15. Apparatus according to claim1, further comprising a filling tube extending into the containerinterior space from the upper region to limit a filling level therein.16. Apparatus according to claim 1, further comprising an internal spaceabove said at least one capillary passage for holding liquid clear ofsaid at least one passage with the container inverted.
 17. Dispensingapparatus for a volatile liquid comprising a container having asubstantially closed interior space for the liquid and annular capillarypassage extending across an upper region of the interior space adjacentan upper portion of an upwardly extending side wall of the containersymmetrically around the container, and an emanator in contact with saidpassage at a center of an annulus of said passage, whereby only liquiddisplaced onto said upper wall portion can reach the capillary passageto be drawn therethrough to the emanator and dispensed therefrom,wherein the container is rotationally symmetrical and is held byresilient means to be tiltable in any direction transverse to an axis ofsymmetry.
 18. Apparatus according to claim 17, wherein the annularcapillary passage is planar.